A wheeled excavator travel merging control system and control method

Abstract

The present invention discloses a travel merging control system and control method for a wheeled excavator, comprising an engine, a main pump assembly, a pilot valve group, a main valve, a travel motor, and a travel merging valve. The engine is used to drive the main pump assembly. The main pump assembly includes a first main pump and a second main pump for supplying oil to the main valve. The main valve includes a travel valve core and a second valve core, the travel valve core being connected to the pilot valve group and the travel motor, respectively. The pilot valve group controls the travel valve core to switch the travel motor forward or reverse. The main pump assembly is connected to the main valve via a travel merging valve. The travel merging valve is used to adjust the output direction of the first and second main pumps, so that in the operating mode, the first main pump supplies oil to the second valve core, and the second main pump supplies oil to the travel valve core. In the travel mode, the first and second main pumps merge to supply oil to the travel valve core. By merging the two pumps, the engine speed and the main pump displacement are reduced, significantly reducing vehicle fuel consumption and noise, and achieving greater energy efficiency and comfort.

Description

Technical Field

[0001] The present invention belongs to the technical field of excavators, and more specifically, relates to a walking merging control system and a control method for a wheeled excavator. Background Art

[0002] Wheeled hydraulic excavators are highly sought after for their maneuverability and rapid site transition, and are widely used in road and bridge infrastructure, urban and rural construction, and other applications. Unlike crawler hydraulic excavators, the travel mechanism of a wheeled hydraulic excavator relies on a hydraulic motor driving a transmission, which in turn drives the front and rear axles via a drive shaft, thereby driving the tires mounted on these axles.

[0003] With the growing market share in recent years, customer demands for vehicle travel speed and energy efficiency have also increased. Wheeled hydraulic excavators typically have two operating modes: work mode and travel mode. In work mode, the excavator can be used for operations involving the vehicle's work device, short periods of dismounting and walking, or a combination of both. When long-distance travel is required, the vehicle must be switched to travel mode. For safety reasons, only walking operations are possible, with no access to the vehicle.

[0004] Currently, to ensure the combined motion of wheel excavators, travel is typically supplied by a single pump. However, long-distance travel typically requires higher travel speeds. To increase travel speed, the current practice is to maximize the displacement of the single pump and the engine speed to meet the travel motor's flow requirements. This results in increased engine fuel consumption, increased vehicle noise, and reduced fuel efficiency and comfort. Summary of the Invention

[0005] The purpose of the present invention is to provide a wheeled excavator walking merging control method to solve the above problems.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A travel merging control system for a wheeled excavator includes an engine, a main pump assembly, a pilot valve group, a main valve, a travel motor and a travel merging valve;

[0008] The engine is used to drive the main pump assembly;

[0009] The main pump assembly is connected to the hydraulic oil tank and includes a first main pump and a second main pump for supplying oil to the main valve;

[0010] The main valve includes a travel valve core and a second valve core, the travel valve core is connected to the pilot valve group and the travel motor respectively, the pilot valve group is connected to the hydraulic oil tank, and controls the reversal of the travel valve core to make the travel motor rotate forward or reverse;

[0011] The main pump assembly is connected to the main valve through a travel merging valve, and the travel merging valve is used to adjust the output oil direction of the first main pump and the second main pump, so that in the working mode, the first main pump supplies oil to the second valve core, and the second main pump supplies oil to the travel valve core; in the travel mode, the first main pump and the second main pump merge to supply oil to the travel valve core.

[0012] The engine control terminal, the pilot valve group control terminal, and the travel converging valve control terminal are electrically connected to a controller. The controller can control the engine speed through a control program and further control the forward / reverse / stop of the travel motor by controlling the on / off of the pilot valve group.

[0013] Furthermore, the A port and B port of the travel merging valve are respectively connected to the output oil ports of the first main pump and the second main pump, and the C port and D port of the travel merging valve are respectively connected to the input oil ports of the main valve; the travel merging valve internally includes a two-position three-way hydraulically controlled reversing valve and a two-position three-way electromagnetic reversing valve, which are used to control the on and off of the first main pump, the second valve core and the travel valve core.

[0014] Furthermore, the C port of the traveling merging valve is connected to the second valve core of the main valve, the D port of the traveling merging valve is connected to the traveling valve core of the main valve, the first main pump is connected to the C port or the D port through a two-position three-way hydraulically controlled reversing valve, and the second main pump is connected to the D port.

[0015] Furthermore, the main pump assembly also includes a pilot pump. The E port of the travel converging valve is connected to the output oil port of the pilot pump, providing pre-valve pressure oil to the two-position three-way solenoid reversing valve. The output oil of the pilot pump drives the two-position three-way hydraulic control reversing valve through the two-position three-way solenoid reversing valve to reverse the direction.

[0016] Furthermore, two one-way valves are provided at the input end of the D port in the travel merging valve to prevent flow backflow and mutual communication between the two pumps during merging, thereby protecting the main pump from damage.

[0017] Furthermore, an internal merging channel is provided inside the walking merging valve. In the walking mode, the hydraulic oil output by the first main pump enters the main valve through the internal merging channel. The merging channel is reserved to facilitate vehicle pipeline connection.

[0018] Furthermore, the first main pump and the second main pump are respectively connected to the first solenoid valve and the second solenoid valve; the control end of the first solenoid valve and the control end of the second solenoid valve are both connected to the controller, and the controller adjusts the displacement of the first main pump and the second main pump by controlling the first solenoid valve and the second solenoid valve.

[0019] The present invention also provides a walking merging control method for a wheeled excavator, which is based on the above control system and includes the following steps:

[0020] When the wheeled excavator is in working mode, the travel merging valve is controlled so that the hydraulic oil output by the first main pump and the second main pump passes through the travel merging valve but does not merge, and supplies oil to the second valve core and the travel valve core respectively;

[0021] When the wheeled excavator is in travel mode, the travel merging valve is controlled to merge the hydraulic oil output by the first main pump and the second main pump to supply oil to the travel valve core; at the same time, by controlling the first solenoid valve and the second solenoid valve, the displacement of the first main pump and the second main pump is reduced, thereby reducing the engine speed.

[0022] Furthermore, when the wheeled excavator is in working mode, the directions of the two-position three-way electromagnetic reversing valve and the three-way hydraulically controlled reversing valve inside the travel merging valve are controlled so that the first main pump and the second valve core of the main valve are connected, and the second main pump and the travel valve core of the main valve are connected.

[0023] Furthermore, when the wheeled excavator is in walking mode, the direction of the two-position three-way electromagnetic reversing valve inside the walking merging valve is controlled to drive the two-position three-way hydraulically controlled reversing valve to reverse, so that the first main pump and the second main pump are connected to the walking valve core of the main valve.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The wheeled excavator travel merging control system and control method disclosed herein utilizes a travel merging valve to enable dual pump merging in travel mode, thereby reducing engine speed and main pump displacement. This significantly reduces vehicle fuel consumption and noise, resulting in greater energy efficiency and comfort. Furthermore, this system avoids energy loss in the first main pump during travel mode, lowering vehicle fuel consumption and preventing unnecessary increases in hydraulic oil temperature.

[0026] The traveling merging valve of the present invention is located outside the main valve instead of being integrated into the main valve, so that the pressure loss is lower and the processing is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the hydraulic system control scheme of a wheeled excavator for comparison;

[0028] Figure 2 This is a control relationship diagram of the wheeled excavator travel merging control system according to an embodiment of the present invention.

[0029] In the figure: 1. Engine; 2. Main pump assembly; 2-1. First main pump; 2-2. Second main pump; 2-3. Pilot pump; 2-4. First solenoid valve; 2-5. Second solenoid valve; 3. Hydraulic oil tank; 4. Pilot valve group; 5. Main valve; 5-1. Second valve core; 5-2. Travel valve core; 6. Travel motor; 7. Travel combining valve; 7-1. Two-position three-way hydraulically controlled reversing valve; 7-2. Two-position three-way solenoid reversing valve; 7-3. Check valve. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and specific examples.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0032] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0033] Comparative Example 1

[0034] Figure 1 This is a schematic diagram of the control scheme for the hydraulic system of a comparative wheeled excavator. As shown, engine 1 drives main pump assembly 2, providing power to the hydraulic system. The oil outputs of the first and second main pumps 2-1 and 2-2 are connected to the two oil inputs of the main valve via high-pressure hoses. High-pressure oil is supplied to the second valve core 5-1 by the first main pump 2-1. The travel valve core 5-2, also supplied by the second main pump 2-2, is controlled by the pilot valve assembly 4, which switches the travel valve core 5-2, rotating the travel motor 6 forward or reverse, driving the vehicle forward or reverse. The first and second solenoid valves 2-4 and 2-5 adjust the displacement of the main pumps as needed to achieve energy savings.

[0035] Since the travel motor 6 can only be supplied with oil by the second main pump 2-2, and the displacement is limited, in order to increase the vehicle's travel speed, the second solenoid valve 2-5 is required to adjust the displacement of the second main pump 2-2 to the maximum, and the engine 1 speed is increased to the highest. At this time, not only is the fuel consumption of the engine 1 high, but it is also very noisy and has a low comfort level.

[0036] In the walking mode, the boarding action is locked, and the first main pump is also driven by the maximum speed of the engine 1. The output oil returns to the oil tank through the internal channel of the main valve 5, causing energy loss and also causing the hydraulic oil temperature to rise.

[0037] Example 1

[0038] like Figure 2 The shown embodiment shows a travel merging control system for a wheeled excavator, comprising an engine 1 , a main pump assembly 2 , a pilot valve group 4 , a main valve 5 , a travel motor 6 and a travel merging valve 7 .

[0039] The engine 1 is used to drive the main pump assembly 2 .

[0040] The main pump assembly 2 is connected to the hydraulic oil tank 3. The main pump assembly 2 includes a first main pump 2-1, a second main pump 2-2, a pilot pump 2-3, a first solenoid valve 2-4 and a second solenoid valve 2-5. The first main pump 2-1 and the second main pump 2-2 are used to supply oil to the main valve 5; the first solenoid valve 2-4 and the second solenoid valve 2-5 are used to adjust the displacement of the first main pump 2-1 and the second main pump 2-2.

[0041] The main valve 5 includes a travel valve core 5-2 and a second valve core 5-1. The travel valve core 5-2 is connected to the pilot valve group 4 and the travel motor 6 respectively. The pilot valve group 4 is connected to the hydraulic oil tank 3 and is used to control the reversing of the travel valve core 5-2 to make the travel motor 6 rotate forward or reverse.

[0042] The main pump assembly 2 is connected to the main valve 5 via a travel merging valve 7. The travel merging valve 7 is used to adjust the output oil direction of the first main pump 2-1 and the second main pump 2-2, so that in the working mode, the first main pump 2-1 supplies oil to the second valve core 5-1, and the second main pump 2-2 supplies oil to the travel valve core; in the travel mode, the first main pump 2-1 and the second main pump 2-2 merge to supply oil to the travel valve core 5-2.

[0043] The travel merging valve 7 internally includes a two-position, three-way hydraulically controlled reversing valve 7-1, a two-position, three-way solenoid-controlled reversing valve 7-2, and two one-way valves 7-3. It also has an internal merging channel L. Ports A and B of the travel merging valve 7 are connected to the oil output ports of the first and second main pumps 2-1 and 2-2, respectively, via high-pressure hoses. Ports C and D of the travel merging valve 7 are connected to the oil input ports of the second spool 5-1 of the main valve 5 and the travel spool 5-2, respectively. Two one-way valves 7-3 are provided at the input end of port D, allowing the first main pump 2-1 to communicate with port C or port D through the two-position, three-way hydraulically controlled reversing valve 7-1, thereby controlling the on-off connection between the first main pump 2-1, the second spool 5-1, and the travel spool 5-2. The second main pump 2-2 is always connected to port D via the internal merging channel L and the one-way valves 7-3. The E port of the travel merging valve 7 is connected to the output oil port of the pilot pump 2-3, providing the valve front pressure oil for the two-position three-way electromagnetic reversing valve 7-2. The output oil of the pilot pump 2-3 drives the two-position three-way hydraulic control reversing valve 7-1 to reverse through the two-position three-way electromagnetic reversing valve 7-2.

[0044] The control terminals of the engine 1, the first solenoid valve 2-4, the second solenoid valve 2-5, the pilot valve group 4, and the travel combining valve 7 are electrically connected to a controller. The controller controls the engine 1 speed through a program; adjusts the displacement of the first and second main pumps 2-1 and 2-2 by controlling the first and second solenoid valves 2-4 and 2-5; and further controls the forward / reverse rotation / stop of the travel motor 6 by switching the pilot valve group 4 on and off.

[0045] Example 2

[0046] This embodiment provides a method for controlling a wheeled excavator's travel merging, based on the control system described in Example 1, including the following steps:

[0047] When the wheeled excavator is in working mode, the two-position three-way electromagnetic reversing valve 7-2 is controlled to be in the normal lower position, and the two-position three-way hydraulically controlled reversing valve 7-1 is in the normal left position. At this time, the hydraulic oil output by the first main pump 2-1 enters the main valve through the travel merging valve 7 to supply oil to the second valve core 5-1. The hydraulic oil output by the second main pump 2-2 enters the main valve 5 through the internal merging channel L of the travel merging valve 7 and the one-way valve 7-3 to supply oil to the travel valve core 5-2. At this time, the travel does not merge, and the travel merging valve 7 does not function.

[0048] When the wheeled excavator is in travel mode, the two-position, three-way solenoid directional valve 7-2 is controlled to switch to the upper position. The output of the pilot pump 2-3 flows through the two-position, three-way solenoid directional valve 7-2, driving the two-position, three-way hydraulically controlled directional valve 7-1 to switch to the right position. At this time, the hydraulic oil output by the first main pump 2-1 enters the main valve 5 through the travel merging valve 7 and the check valve 7-3, supplying oil to the travel spool 5-2. The hydraulic oil output by the second main pump 2-2 flows through the internal merging channel L of the travel merging valve 7 and the check valve 7-3. After the two pumps' flows merge, they enter the main valve 5 and supply oil to the travel spool 5-2. Simultaneously, the controller outputs current to control the first and second solenoid valves 2-4 and 2-5, reducing the displacement of the first and second main pumps 2-1 and 2-2, and simultaneously lowering the engine 1 speed. The output flow rate still meets the required travel speed, thus reducing the engine 1 speed while avoiding flow loss in the first main pump 2-1.

[0049] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative and non-exhaustive, and is not intended to be limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and technical principles of the described embodiments, and such modifications and variations should be considered within the scope of the present invention.

Claims

1. A wheeled excavator travel merging control system, characterized in that: Includes engine, main pump assembly, pilot valve group, main valve, travel motor and travel converging valve; The engine is used to drive the main pump assembly; The main pump assembly is connected to the hydraulic oil tank and includes a first main pump and a second main pump for supplying oil to the main valve; The main valve includes a travel valve core and a second valve core, the travel valve core is connected to the pilot valve group and the travel motor respectively, and the pilot valve group is connected to the hydraulic oil tank for controlling the reversing of the travel valve core to make the travel motor rotate forward or reverse; The main pump assembly is connected to the main valve via a travel merging valve, which is used to adjust the output oil direction of the first main pump and the second main pump, so that in the working mode, the first main pump supplies oil to the second valve core, and the second main pump supplies oil to the travel valve core; in the travel mode, the first main pump and the second main pump merge to supply oil to the travel valve core; The A and B ports of the travel merging valve are connected to the oil output ports of the first and second main pumps respectively, and the C and D ports of the travel merging valve are connected to the oil input ports of the main valves respectively; the travel merging valve internally includes a two-position three-way hydraulically controlled reversing valve and a two-position three-way electromagnetic reversing valve for controlling the on-off of the first main pump, the second valve core, and the travel valve core; The C port of the traveling merging valve is connected to the second valve core of the main valve, and the D port of the traveling merging valve is connected to the traveling valve core of the main valve. The first main pump is connected to the C port or the D port through a two-position three-way hydraulically controlled reversing valve, and the second main pump is connected to the D port.

2. The wheeled excavator travel merging control system according to claim 1, characterized in that: The main pump assembly also includes a pilot pump. The E port of the travel merging valve is connected to the output oil port of the pilot pump to provide pre-valve pressure oil for the two-position three-way solenoid reversing valve. The output oil of the pilot pump drives the two-position three-way hydraulically controlled reversing valve to reverse through the two-position three-way solenoid reversing valve.

3. The wheeled excavator travel merging control system according to claim 1, characterized in that: The input end of the D port in the travel merging valve is further provided with two one-way valves.

4. The wheeled excavator travel merging control system according to claim 1, characterized in that: An internal merging channel is also provided inside the walking merging valve. In the walking mode, the hydraulic oil output by the first main pump enters the main valve through the internal merging channel.

5. The wheeled excavator travel merging control system according to claim 1, characterized in that: The first main pump and the second main pump are connected to the first solenoid valve and the second solenoid valve respectively; the displacement of the first main pump and the second main pump is adjusted by controlling the first solenoid valve and the second solenoid valve.

6. A method for controlling the movement and merging of a wheeled excavator, based on the control system according to any one of claims 1 to 5, characterized in that: The following steps are involved: When the wheeled excavator is in working mode, the travel merging valve is controlled so that the hydraulic oil output by the first main pump and the second main pump passes through the travel merging valve but does not merge, and supplies oil to the second valve core and the travel valve core respectively; When the wheeled excavator is in travel mode, the travel merging valve is controlled to merge the hydraulic oil output by the first main pump and the second main pump to supply oil to the travel valve core; at the same time, the displacement of the first main pump and the second main pump is reduced to reduce the engine speed.

7. The wheeled excavator travel merging control method according to claim 6, characterized in that: When the wheeled excavator is in working mode, the directions of the two-position three-way electromagnetic reversing valve and the two-position three-way hydraulically controlled reversing valve inside the travel combining valve are controlled so that the first main pump is connected to the second valve core of the main valve, and the second main pump is connected to the travel valve core of the main valve.

8. The wheeled excavator travel merging control method according to claim 6, characterized in that: When the wheeled excavator is in walking mode, the direction of the two-position three-way electromagnetic reversing valve inside the walking merging valve is controlled to drive the two-position three-way hydraulically controlled reversing valve to reverse, so that the first main pump and the second main pump are connected to the walking valve core of the main valve.

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